1. Field of the Invention
The present invention relates to an inflator suitable for an air bag system for an automobile. The present invention also provides an inflator in which pieces of a broken rupturable plate or combustion residues of a gas generating agent are prevented from flowing out of the inflator.
2. Description of the Related Art
As an inflator used in an air bag system for an automobile, there is a type in which an air bag is inflated by using only combustion gas of a gas generating agent and also a type in which an air bag is inflated by using combustion gas of a gas generating agent and pressurized gas. In either type of inflators, it is required that combustion residues generated at the time of combustion of the gas generating agent, for example, powdery metal or metal oxide generated due to components of the gas generating agent are never discharged into the air bag. Therefore, such a trial has been made that generation of combustion residues is suppressed by changing composition of the gas generating agent or a structure of the inflator.
In addition, there is a type in which an air bag is inflated by using only pressurized gas. However, with a development of an inflator for an inflating-type safety system for an automobile, an inflator using pressurized gas and a gas generating agent together is attracting attention.
Also, such a trial has been made that a filter is disposed to prevent pieces of a broken rupturable plate from flowing outside, or that generation of combustion residues is suppressed by changing composition of the gas generating agent, or a structure of the inflator.
As related art, there are JP-A 9-76870, U.S. Pat. No. 3,966,226, and U.S. Pat. No. 4,018,457.
An essential requirement in designing the inflator is that an air bag has to be inflated by a predetermined amount within a predetermined time to actuate the air bag effectively, and various proposals about the structure have been made conventionally. For example, there is JP-A 8-282427. As other related art, there have been known JP-B 44-10443, U.S. Pat. No. 6,189,922, and JP-A 2002-166817.
Since the inflator is installed in an automobile, the weight and size of the inflator which influences a weight of an automobile are important design requirements. Accordingly, further reduction in weight of an inflator is required while maintaining its original functions.